The objective of this proposal is to understand how people perceive tactile patterns. The project will focus on the processing of tactile spatial patterns. Studies will be conducted comparing interactions between spatial patterns presented to the same location and to separate locations. Results from the psychophysical and perceptual measures will be related to neurophysiological studies of peripheral and central responses to tactile stimuli. Tactile spatial patterns will be generated by means of several types of displays. One is the newly-developed dense array, which consists of 400 independently-controlled tactors in a 20 x 20 matrix. The center-to-center spacing of the contactor points can be varied from 0.5 mm to 1.0 mm. The dense array will be used to generate spatial patterns that selectively activate different populations of mechanoreceptors and to study spatial sensitivity on the fingerpad and palm. The dense array will also be used to examine the conditions for producing perceptual changes related to sensory plasticity. Studies will be conducted with the dense array as well as arrays from the Optacon, a reading aid for the blind, to investigate such perceptual phenomena as temporal integration, temporal masking, response competition, and selective attention. Measurements will also be made of subjects' abilities to resolve spatial gratings. One of the aims of the project is to compare the results obtained with tactile stimuli to studies conducted with visual and auditory stimuli. Results from the project will be relevant to the development of cutaneous communication systems for the deaf, blind, and deaf-blind and to the measurement and understanding of neurological problems.